Is that like Joe's "brain cloud" in Joe Vs. The Volcano? Heck no! It's a way to granularly categorize web content into a near-infinite set of categories (called folksomies ) with the use of tags. For a more complete explanation see Tag Clouds at Wikipedia.com. There are tremendous SEO benefits of tag clouds as they help search engines better index your pages. To see my cloud, click "Cloud" in the menu on the left.